<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
		#form{
			width: 400px;
			height: 400px;
			background: red url() 0 0 no-repeat;
			overflow: scroll;
		}
	</style>
	<script type="text/javascript">
		window.onload= function () {
			btn = document.getElementById('btn');

			form = document.getElementById('form');

			btn.onclick= function () {
				form.innerHTML = form.innerHTML+"<p>姓名：<input type=\"text\" name=\"\"></p>";
			}

		}
	</script>
</head>
<body>
	<button id='btn'>增加</button>
	<form id="form">
		
	</form>

</body>
</html>